Remove stale lockfiles if created on the same node.

2 files changed, 348 insertions, 257 deletions

diff --git a/jnlib/ChangeLog b/jnlib/ChangeLog
index 61d12d580..5511dedcd 100644
--- a/jnlib/ChangeLog
+++ b/jnlib/ChangeLog
@@ -1,3 +1,15 @@
+2006-06-28  Werner Koch  <wk@g10code.com>
+
+	* dotlock.c (make_dotlock, release_dotlock, read_lockfile)
+	(maybe_deadlock, destroy_dotlock, create_dotlock): Re-indented.
+	(create_dotlock): Repalces some log_fatal by log_error as it was
+	not intended that they should terminate.  Write the nodename to
+	the locking file. Code cleanups.
+	(read_lockfile): Reworked to read the node name.
+	(make_dotlock): Test for identical node name and delete lock stale
+	file.
+	(release_dotlock): Likewise.
+
 2006-05-23  Werner Koch  <wk@g10code.com>
 
 	* libjnlib-config.h (JNLIB_NEED_UTF8CONV): Fixed typo in name.
diff --git a/jnlib/dotlock.c b/jnlib/dotlock.c
index 89edb7b91..f5de8fa54 100644
--- a/jnlib/dotlock.c
+++ b/jnlib/dotlock.c
@@ -1,6 +1,6 @@
 /* dotlock.c - dotfile locking
  * Copyright (C) 1998, 2000, 2001, 2003, 2004, 
- *               2005 Free Software Foundation, Inc.
+ *               2005, 2006 Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
  *
@@ -55,32 +55,35 @@
 #endif
 
 
-struct dotlock_handle {
-    struct dotlock_handle *next;
-    char *tname;    /* name of lockfile template */
-    char *lockname; /* name of the real lockfile */
-    int locked;     /* lock status */
-    int disable;    /* locking */
+struct dotlock_handle 
+{
+  struct dotlock_handle *next;
+  char *tname;    /* Name of lockfile template.  */
+  size_t nodename_off; /* Offset in TNAME of the nodename part. */
+  size_t nodename_len; /* Length of the nodename part. */
+  char *lockname; /* Name of the real lockfile.  */
+  int locked;     /* Lock status.  */
+  int disable;    /* When true, locking is disabled.  */
 };
 
 
 static volatile DOTLOCK all_lockfiles;
 static int never_lock;
 
-static int read_lockfile( const char *name );
+static int read_lockfile (DOTLOCK h, int *same_node);
 
 void
 disable_dotlock(void)
 {
-    never_lock = 1;
+  never_lock = 1;
 }
 
 /****************
  * Create a lockfile with the given name and return an object of
  * type DOTLOCK which may be used later to actually do the lock.
  * A cleanup routine gets installed to cleanup left over locks
- * or other files used together with the lockmechanism.
- * Althoug the function is called dotlock, this does not necessarily
+ * or other files used together with the lock mechanism.
+ * Although the function is called dotlock, this does not necessarily
  * mean that real lockfiles are used - the function may decide to
  * use fcntl locking.  Calling the function with NULL only install
  * the atexit handler and maybe used to assure that the cleanup
@@ -94,160 +97,165 @@ disable_dotlock(void)
 DOTLOCK
 create_dotlock( const char *file_to_lock )
 {
-    static int initialized;
-    DOTLOCK h;
-    int  fd = -1;
-    char pidstr[16];
-  #ifndef  HAVE_DOSISH_SYSTEM
-    struct utsname utsbuf;
-  #endif
-    const char *nodename;
-    const char *dirpart;
-    int dirpartlen;
-
-    if( !initialized ) {
-	atexit( dotlock_remove_lockfiles );
-	initialized = 1;
+  static int initialized;
+  DOTLOCK h;
+  int  fd = -1;
+  char pidstr[16];
+  const char *nodename;
+  const char *dirpart;
+  int dirpartlen;
+#ifndef  HAVE_DOSISH_SYSTEM
+  struct utsname utsbuf;
+#endif
+
+  if ( !initialized )
+    {
+      atexit( dotlock_remove_lockfiles );
+      initialized = 1;
     }
-    if( !file_to_lock )
-	return NULL;
+  if ( !file_to_lock )
+    return NULL;  /* Only initialization was requested.  */
 
-    h = jnlib_xcalloc( 1, sizeof *h );
-    if( never_lock ) {
-	h->disable = 1;
+  h = jnlib_xcalloc ( 1, sizeof *h );
+  if( never_lock )
+    {
+      h->disable = 1;
 #ifdef _REENTRANT
-	/* fixme: aquire mutex on all_lockfiles */
+      /* fixme: aquire mutex on all_lockfiles */
 #endif
-	h->next = all_lockfiles;
-	all_lockfiles = h;
-	return h;
+      h->next = all_lockfiles;
+      all_lockfiles = h;
+      return h;
     }
 
 #ifndef HAVE_DOSISH_SYSTEM
-    sprintf( pidstr, "%10d\n", (int)getpid() );
-    /* fixme: add the hostname to the second line (FQDN or IP addr?) */
-
-    /* create a temporary file */
-    if( uname( &utsbuf ) )
-	nodename = "unknown";
-    else
-	nodename = utsbuf.nodename;
-
+  sprintf (pidstr, "%10d\n", (int)getpid() );
+  /* fixme: add the hostname to the second line (FQDN or IP addr?) */
+
+  /* Create a temporary file. */
+  if ( uname ( &utsbuf ) )
+    nodename = "unknown";
+  else
+    nodename = utsbuf.nodename;
+  
 #ifdef __riscos__
-    {
-        char *iter = (char *) nodename;
-        for (; iter[0]; iter++)
-            if (iter[0] == '.')
-                iter[0] = '/';
-    }
+  {
+    char *iter = (char *) nodename;
+    for (; iter[0]; iter++)
+      if (iter[0] == '.')
+        iter[0] = '/';
+  }
 #endif /* __riscos__ */
 
-    if( !(dirpart = strrchr( file_to_lock, DIRSEP_C )) ) {
-	dirpart = EXTSEP_S;
-	dirpartlen = 1;
+  if ( !(dirpart = strrchr ( file_to_lock, DIRSEP_C )) )
+    {
+      dirpart = EXTSEP_S;
+      dirpartlen = 1;
     }
-    else {
-	dirpartlen = dirpart - file_to_lock;
-	dirpart = file_to_lock;
+  else
+    {
+      dirpartlen = dirpart - file_to_lock;
+      dirpart = file_to_lock;
     }
 
 #ifdef _REENTRANT
     /* fixme: aquire mutex on all_lockfiles */
 #endif
-    h->next = all_lockfiles;
-    all_lockfiles = h;
+  h->next = all_lockfiles;
+  all_lockfiles = h;
 
-    h->tname = jnlib_xmalloc( dirpartlen + 6+30+ strlen(nodename) + 11 );
+  h->tname = jnlib_xmalloc ( dirpartlen + 6+30+ strlen(nodename) + 11 );
+  h->nodename_len = strlen (nodename);
 #ifndef __riscos__
-     sprintf( h->tname, "%.*s/.#lk%p.%s.%d",
-	     dirpartlen, dirpart, h, nodename, (int)getpid() );
+  sprintf (h->tname, "%.*s/.#lk%p.", dirpartlen, dirpart, h );
+  h->nodename_off = strlen (h->tname);
+  sprintf (h->tname+h->nodename_off, "%s.%d", nodename, (int)getpid ());
 #else /* __riscos__ */
-    sprintf( h->tname, "%.*s.lk%p/%s/%d",
-	     dirpartlen, dirpart, h, nodename, (int)getpid() );
+  sprintf (h->tname, "%.*s.lk%p/", dirpartlen, dirpart, h );
+  h->nodename_off = strlen (h->tname);
+  sprintf (h->tname+h->nodename_off, "%s/%d", nodename, (int)getpid () );
 #endif /* __riscos__ */
 
-    do {
-	errno = 0;
-	fd = open( h->tname, O_WRONLY|O_CREAT|O_EXCL,
-			  S_IRUSR|S_IRGRP|S_IROTH|S_IWUSR );
-    } while( fd == -1 && errno == EINTR );
-    if( fd == -1 ) {
-	all_lockfiles = h->next;
-	log_error( "failed to create temporary file `%s': %s\n",
-					    h->tname, strerror(errno));
-	jnlib_free(h->tname);
-	jnlib_free(h);
-	return NULL;
-    }
-    if( write(fd, pidstr, 11 ) != 11 ) {
-	all_lockfiles = h->next;
-      #ifdef _REENTRANT
-	/* release mutex */
-      #endif
-	log_fatal( "error writing to `%s': %s\n", h->tname, strerror(errno) );
-	close(fd);
-	unlink(h->tname);
-	jnlib_free(h->tname);
-	jnlib_free(h);
-	return NULL;
-    }
-    if( close(fd) ) {
-	all_lockfiles = h->next;
-      #ifdef _REENTRANT
-	/* release mutex */
-      #endif
-	log_fatal( "error writing to `%s': %s\n", h->tname, strerror(errno) );
-	close(fd);
-	unlink(h->tname);
-	jnlib_free(h->tname);
-	jnlib_free(h);
-	return NULL;
+  do 
+    {
+      errno = 0;
+      fd = open (h->tname, O_WRONLY|O_CREAT|O_EXCL,
+                 S_IRUSR|S_IRGRP|S_IROTH|S_IWUSR );
+    } 
+  while (fd == -1 && errno == EINTR);
+
+  if ( fd == -1 ) 
+    {
+      all_lockfiles = h->next;
+      log_error ( "failed to create temporary file `%s': %s\n",
+                  h->tname, strerror(errno));
+      jnlib_free(h->tname);
+      jnlib_free(h);
+      return NULL;
     }
+  if ( write (fd, pidstr, 11 ) != 11 )
+    goto write_failed;
+  if ( write (fd, nodename, strlen (nodename) ) != strlen (nodename) )
+    goto write_failed;
+  if ( write (fd, "\n", 1 ) != 1 )
+    goto write_failed;
+  if ( close (fd) )
+    goto write_failed;
 
 # ifdef _REENTRANT
-    /* release mutex */
+  /* release mutex */
 # endif
 #endif /* !HAVE_DOSISH_SYSTEM */
-    h->lockname = jnlib_xmalloc( strlen(file_to_lock) + 6 );
-    strcpy(stpcpy(h->lockname, file_to_lock), EXTSEP_S "lock");
-    return h;
+  h->lockname = jnlib_xmalloc ( strlen (file_to_lock) + 6 );
+  strcpy (stpcpy(h->lockname, file_to_lock), EXTSEP_S "lock");
+  return h;
+ write_failed:
+  all_lockfiles = h->next;
+# ifdef _REENTRANT
+  /* fixme: release mutex */
+# endif
+  log_error ( "error writing to `%s': %s\n", h->tname, strerror(errno) );
+  close(fd);
+  unlink(h->tname);
+  jnlib_free(h->tname);
+  jnlib_free(h);
+  return NULL;
 }
 
 
 void
 destroy_dotlock ( DOTLOCK h )
 {
-#if !defined (HAVE_DOSISH_SYSTEM)
-    if ( h )
-      {
-        DOTLOCK hprev, htmp;
-
-        /* First remove the handle from our global list of all locks. */
-        for (hprev=NULL, htmp=all_lockfiles; htmp; hprev=htmp, htmp=htmp->next)
-          if (htmp == h)
-            {
-              if (hprev)
-                hprev->next = htmp->next;
-              else
-                all_lockfiles = htmp->next;
-              h->next = NULL;
-              break;
-            }
-
-        /* Second destroy the lock. */
-	if (!h->disable)
+#ifndef HAVE_DOSISH_SYSTEM
+  if ( h )
+    {
+      DOTLOCK hprev, htmp;
+      
+      /* First remove the handle from our global list of all locks. */
+      for (hprev=NULL, htmp=all_lockfiles; htmp; hprev=htmp, htmp=htmp->next)
+        if (htmp == h)
           {
-	    if (h->locked && h->lockname)
-              unlink (h->lockname);
-            if (h->tname)
-              unlink (h->tname);
-	    jnlib_free (h->tname);
-	    jnlib_free (h->lockname);
+            if (hprev)
+              hprev->next = htmp->next;
+            else
+              all_lockfiles = htmp->next;
+            h->next = NULL;
+            break;
           }
-	jnlib_free(h);
-
-      }
-#endif
+      
+      /* Second destroy the lock. */
+      if (!h->disable)
+        {
+          if (h->locked && h->lockname)
+            unlink (h->lockname);
+          if (h->tname)
+              unlink (h->tname);
+          jnlib_free (h->tname);
+          jnlib_free (h->lockname);
+        }
+      jnlib_free(h);
+    }
+#endif /*!HAVE_DOSISH_SYSTEM*/
 }
 
 
@@ -255,107 +263,120 @@ destroy_dotlock ( DOTLOCK h )
 static int
 maybe_deadlock( DOTLOCK h )
 {
-    DOTLOCK r;
+  DOTLOCK r;
 
-    for( r=all_lockfiles; r; r = r->next ) {
-	if( r != h && r->locked )
-	    return 1;
+  for ( r=all_lockfiles; r; r = r->next )
+    {
+      if ( r != h && r->locked )
+        return 1;
     }
-    return 0;
+  return 0;
 }
 
 /****************
- * Do a lock on H. A TIMEOUT of 0 returns immediately,
- * -1 waits forever (hopefully not), other
- * values are timeouts in milliseconds.
- * Returns: 0 on success
+ * Do a lock on H. A TIMEOUT of 0 returns immediately, -1 waits
+ * forever (hopefully not), other values are reserved (should then be
+ * timeouts in milliseconds).  Returns: 0 on success
  */
 int
 make_dotlock( DOTLOCK h, long timeout )
 {
 #ifdef HAVE_DOSISH_SYSTEM
-    return 0;
+  return 0;
 #else
-    int  pid;
-    const char *maybe_dead="";
-    int backoff=0;
+  int  pid;
+  const char *maybe_dead="";
+  int backoff=0;
+  int same_node;
 
-    if( h->disable ) {
-	return 0;
-    }
+  if ( h->disable )
+    return 0; /* Locks are completely disabled.  Return success. */
 
-    if( h->locked ) {
+  if ( h->locked ) 
+    {
 #ifndef __riscos__
-	log_debug("oops, `%s' is already locked\n", h->lockname );
+      log_debug("oops, `%s' is already locked\n", h->lockname );
 #endif /* !__riscos__ */
-	return 0;
+      return 0;
     }
 
-    for(;;) {
+  for(;;)
+    {
 #ifndef __riscos__
-	if( !link(h->tname, h->lockname) ) {
-	    /* fixme: better use stat to check the link count */
-	    h->locked = 1;
-	    return 0; /* okay */
+      if ( !link(h->tname, h->lockname) )
+        {
+          /* fixme: better use stat to check the link count */
+          h->locked = 1;
+          return 0; /* okay */
 	}
-	if( errno != EEXIST ) {
-	    log_error( "lock not made: link() failed: %s\n", strerror(errno) );
-	    return -1;
+      if ( errno != EEXIST )
+        {
+          log_error( "lock not made: link() failed: %s\n", strerror(errno) );
+          return -1;
 	}
 #else /* __riscos__ */
-        if( !renamefile(h->tname, h->lockname) ) {
-            h->locked = 1;
-            return 0; /* okay */
+      if ( !renamefile(h->tname, h->lockname) ) 
+        {
+          h->locked = 1;
+          return 0; /* okay */
         }
-        if( errno != EEXIST ) {
-	    log_error( "lock not made: rename() failed: %s\n", strerror(errno) );
-	    return -1;
+      if ( errno != EEXIST ) 
+        {
+          log_error( "lock not made: rename() failed: %s\n", strerror(errno) );
+          return -1;
         }
 #endif /* __riscos__ */
-	if( (pid = read_lockfile(h->lockname)) == -1 ) {
-	    if( errno != ENOENT ) {
-		log_info("cannot read lockfile\n");
-		return -1;
+
+      if ( (pid = read_lockfile (h, &same_node)) == -1 ) 
+        {
+          if ( errno != ENOENT )
+            {
+              log_info ("cannot read lockfile\n");
+              return -1;
 	    }
-	    log_info( "lockfile disappeared\n");
-	    continue;
+          log_info( "lockfile disappeared\n");
+          continue;
 	}
-	else if( pid == getpid() ) {
-	    log_info( "Oops: lock already held by us\n");
-	    h->locked = 1;
-	    return 0; /* okay */
+      else if ( pid == getpid() && same_node )
+        {
+          log_info( "Oops: lock already held by us\n");
+          h->locked = 1;
+          return 0; /* okay */
 	}
-	else if( kill(pid, 0) && errno == ESRCH ) {
+      else if ( same_node && kill (pid, 0) && errno == ESRCH )
+        {
 #ifndef __riscos__
-	    maybe_dead = " - probably dead";
-#if 0 /* we should not do this without checking the permissions */
-	       /* and the hostname */
-	    log_info( "removing stale lockfile (created by %d)", pid );
-#endif
+          log_info ("removing stale lockfile (created by %d)", pid );
+          unlink (h->lockname);
+          continue;
 #else /* __riscos__ */
-            /* we are *pretty* sure that the other task is dead and therefore
-               we remove the other lock file */
-            maybe_dead = " - probably dead - removing lock";
-            unlink(h->lockname);
+          /* Under RISCOS we are *pretty* sure that the other task
+             is dead and therefore we remove the stale lock file. */
+          maybe_dead = " - probably dead - removing lock";
+          unlink(h->lockname);
 #endif /* __riscos__ */
 	}
-	if( timeout == -1 ) {
-	    struct timeval tv;
-	    log_info( "waiting for lock (held by %d%s) %s...\n",
-		      pid, maybe_dead, maybe_deadlock(h)? "(deadlock?) ":"");
-
-
-	    /* can't use sleep, cause signals may be blocked */
-	    tv.tv_sec = 1 + backoff;
-	    tv.tv_usec = 0;
-	    select(0, NULL, NULL, NULL, &tv);
-	    if( backoff < 10 )
-		backoff++ ;
+
+      if ( timeout == -1 ) 
+        {
+          /* Wait until lock has been released. */
+          struct timeval tv;
+          
+          log_info ("waiting for lock (held by %d%s) %s...\n",
+                    pid, maybe_dead, maybe_deadlock(h)? "(deadlock?) ":"");
+
+
+          /* We can't use sleep, cause signals may be blocked. */
+          tv.tv_sec = 1 + backoff;
+          tv.tv_usec = 0;
+          select(0, NULL, NULL, NULL, &tv);
+          if ( backoff < 10 )
+            backoff++ ;
 	}
-	else
-	    return -1;
+      else
+        return -1;
     }
-    /*not reached */
+    /*NOTREACHED*/
 #endif /* !HAVE_DOSISH_SYSTEM */
 }
 
@@ -368,92 +389,150 @@ int
 release_dotlock( DOTLOCK h )
 {
 #ifdef HAVE_DOSISH_SYSTEM
-    return 0;
+  return 0;
 #else
-    int pid;
+  int pid, same_node;
 
-    /* To avoid atexit race conditions we first check whether there
-       are any locks left.  It might happen that another atexit
-       handler tries to release the lock while the atexit handler of
-       this module already ran and thus H is undefined.  */
-    if(!all_lockfiles)
-        return 0;
+  /* To avoid atexit race conditions we first check whether there are
+     any locks left.  It might happen that another atexit handler
+     tries to release the lock while the atexit handler of this module
+     already ran and thus H is undefined.  */
+  if (!all_lockfiles)
+    return 0;
 
-    if( h->disable ) {
-	return 0;
-    }
+  if ( h->disable )
+    return 0;
 
-    if( !h->locked ) {
-	log_debug("oops, `%s' is not locked\n", h->lockname );
-	return 0;
+  if ( !h->locked )
+    {
+      log_debug("oops, `%s' is not locked\n", h->lockname );
+      return 0;
     }
 
-    pid = read_lockfile( h->lockname );
-    if( pid == -1 ) {
-	log_error( "release_dotlock: lockfile error\n");
-	return -1;
+  pid = read_lockfile (h, &same_node);
+  if ( pid == -1 ) 
+    {
+      log_error( "release_dotlock: lockfile error\n");
+      return -1;
     }
-    if( pid != getpid() ) {
-	log_error( "release_dotlock: not our lock (pid=%d)\n", pid);
-	return -1;
+  if ( pid != getpid() || !same_node )
+    {
+      log_error( "release_dotlock: not our lock (pid=%d)\n", pid);
+      return -1;
     }
 #ifndef __riscos__
-    if( unlink( h->lockname ) ) {
-	log_error( "release_dotlock: error removing lockfile `%s'",
-							h->lockname);
-	return -1;
+  if ( unlink( h->lockname ) )
+    {
+      log_error( "release_dotlock: error removing lockfile `%s'",
+                 h->lockname);
+      return -1;
     }
 #else /* __riscos__ */
-    if( renamefile(h->lockname, h->tname) ) {
-	log_error( "release_dotlock: error renaming lockfile `%s' to `%s'",
-							h->lockname, h->tname);
-	return -1;
+  if ( renamefile(h->lockname, h->tname) ) 
+    {
+      log_error( "release_dotlock: error renaming lockfile `%s' to `%s'",
+                 h->lockname, h->tname);
+      return -1;
     }
 #endif /* __riscos__ */
-    /* fixme: check that the link count is now 1 */
-    h->locked = 0;
-    return 0;
+  /* fixme: check that the link count is now 1 */
+  h->locked = 0;
+  return 0;
 #endif /* !HAVE_DOSISH_SYSTEM */
 }
 
 
-/****************
- * Read the lock file and return the pid, returns -1 on error.
+/*
+   Read the lock file and return the pid, returns -1 on error.  True
+   will be stored at SAME_NODE if the lock file has been created on
+   the same node.
  */
 static int
-read_lockfile( const char *name )
+read_lockfile (DOTLOCK h, int *same_node )
 {
 #ifdef HAVE_DOSISH_SYSTEM
-    return 0;
+  return 0;
 #else
-    int fd, pid;
-    char pidstr[16];
-
-    if( (fd = open(name, O_RDONLY)) == -1 ) {
-	int e = errno;
-	log_debug("error opening lockfile `%s': %s\n", name, strerror(errno) );
-	errno = e;
-	return -1;
+  char buffer_space[10+1+70+1]; /* 70 is just an estimated value; node
+                                   name are usually shorter. */
+  int fd, pid;
+  char *buffer, *p;
+  size_t expected_len;
+  int res, nread;
+  
+  *same_node = 0;
+  expected_len = 10 + 1 + h->nodename_len + 1;
+  if ( expected_len >= sizeof buffer_space)
+    buffer = jnlib_xmalloc (expected_len);
+  else
+    buffer = buffer_space;
+
+  if ( (fd = open (h->lockname, O_RDONLY)) == -1 )
+    {
+      int e = errno;
+      log_info ("error opening lockfile `%s': %s\n",
+                h->lockname, strerror(errno) );
+      if (buffer != buffer_space)
+        jnlib_free (buffer);
+      errno = e; /* Need to return ERRNO here. */
+      return -1;
     }
-    if( read(fd, pidstr, 10 ) != 10 ) {  /* Read 10 digits w/o newline */
-	log_debug("error reading lockfile `%s'", name );
-	close(fd);
-	errno = 0;
-	return -1;
+
+  p = buffer;
+  nread = 0;
+  do
+    {
+      res = read (fd, p, expected_len - nread);
+      if (res == -1 && errno == EINTR)
+        continue;
+      if (res < 0)
+        {
+          log_info ("error reading lockfile `%s'", h->lockname );
+          close (fd); 
+          if (buffer != buffer_space)
+            jnlib_free (buffer);
+          errno = 0; /* Do not return an inappropriate ERRNO. */
+          return -1;
+        }
+      p += res;
+      nread += res;
     }
-    pidstr[10] = 0;  /* terminate pid string */
-    close(fd);
-    pid = atoi(pidstr);
+  while (res && nread != expected_len);
+  close(fd);
+
+  if (nread < 11)
+    {
+      log_info ("invalid size of lockfile `%s'", h->lockname );
+      if (buffer != buffer_space)
+        jnlib_free (buffer);
+      errno = 0; /* Do not return an inappropriate ERRNO. */
+      return -1;
+    }
+
+  if (buffer[10] != '\n'
+      || (buffer[10] = 0, pid = atoi (buffer)) == -1
 #ifndef __riscos__
-    if( !pid || pid == -1 ) {
+      || !pid 
 #else /* __riscos__ */
-    if( (!pid && riscos_getpid()) || pid == -1 ) {
+      || (!pid && riscos_getpid())
 #endif /* __riscos__ */
-	log_error("invalid pid %d in lockfile `%s'", pid, name );
-	errno = 0;
-	return -1;
+      )
+    {
+      log_error ("invalid pid %d in lockfile `%s'", pid, h->lockname );
+      if (buffer != buffer_space)
+        jnlib_free (buffer);
+      errno = 0;
+      return -1;
     }
-    return pid;
+
+  if (nread == expected_len
+      && !memcmp (h->tname+h->nodename_off, buffer+11, h->nodename_len) 
+      && buffer[11+h->nodename_len] == '\n')
+    *same_node = 1;
+
+  if (buffer != buffer_space)
+    jnlib_free (buffer);
+  return pid;
 #endif
 }